3D Printing vs. CNC Machine: Which is Better?

Throughout history, there has been a variety of methods used to manufacture custom parts. Today, the most common methods used are 3D printing and CNC machine. Both utilize computer numerical control (CNC), which developed from traditional milling methods after WWII. While 3D printing has some major breakthroughs in the last few years, CNC machine is still considered a reliable standard. So, the question is: which one is better?

3D Printing

Pros

3D printing has been around for years but only recently became a common manufacturing method. It is a practical way to create custom parts, as innovation and market availability has significantly reduced the cost. 3D printing is the simplest way to go from computer-aided design (CAD) to physical part, which is why production costs are significantly reduced.

In addition, rapid iteration is possible, as parts can be printed in a matter of hours rather than weeks. Printing materials are becoming ever cheaper, and with recent developments from companies like Markforged, printed parts can be as strong as metal and used in final production, not just for testing and prototyping.

Finally, there is no need to hire a skilled machinist with 3D printing, unlike CNC machinists who significantly add to labor costs.

Cons

Although it’s true that you don’t need to hire anyone with special skills to run 3D printers, they are still complicated machines that can malfunction. Unfortunately, this can result in unusable prints.

Another issue with 3D printing is that because parts are printed layer-by-layer they are anisotropic, which can be problematic in testing.

CNC Machine

Pros

When CNC subtractive manufacturing was first developed it was revolutionary. Machinists had the ability to generate parts faster and with more precision than ever before, while designers could have variety in their designs. This meant that production time was significantly faster than previous methods. Today CNC machines are still useful to create fixtures, tooling, and other end-use parts.

CNC machining can be used for tooling, fixturing, and custom end-use parts.

Cons

The biggest drawback of CNC is the expense. Machines are costly and skilled machinists have high labor costs. Plus, in order to manufacture custom end-use parts, time must be taken to create supporting jigs, clamps etc. This means that when a designer has a part made, they must factor in the time and money it takes to generate the supporting parts as well. This is one of the reasons it can take weeks to create a custom part with CNC machine, making iteration basically impossible.

So the question remains, which one is better 3D Printing or CNC?

The truth is, both methods have their pros and cons, but together they can really improve the design and manufacturing process. For example, CNC is still the preferred method for end-use metal parts, as only extremely expensive laser sintering machines can create similar all-metal parts in a 3D printing method. However, 3D printers can be used to generate iterations before a product is sent to an expensive machinist.

In addition, 3D printing is ideal for printing the supporting clamps and jigs that machinists previously had to take time to make. Markforged’s 3D printers in particular can quickly and inexpensively produce extremely strong parts that can be utilized Now, mills and machinists can focus their time and energy solely on custom parts, rather than support pieces. And, since 3D printers can print geometries that CNC machines are unable to replicate, the options for supporting parts are endless.

Therefore, the ideal solution is to utilize both 3D printing and CNC to shorten production time, decrease cost, and streamline the entire design process.

Using 3D printing in tandem with traditional CNC machine technology improves the manufacturing process all the way from CAD to the physical part.

For more information on combining CNC machine and 3D printing to streamline your manufacturing process drop us a line or call us at (408)986-0200.

About NxRev - NxRev is an engineering enablement company that specializes in sales, support, and consulting services for high-level engineering design firms. As the largest PTC partner on the west coast, we sell the entire suite of PTC software, as well as complementary solutions including FloEFD.